Display devices such as liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays have become daily necessities and quietly changed people's lives. People have higher and higher requirements on the quality such as the resolution, color gamut and brightness of the display devices. Recently, 500 PPI (Pixels Per Inch) and 600 PPI products have been developed by the company.
For example, an LCD is usually manufactured by bonding an array substrate and a color filter (CF) substrate together by cell-assembly process. However, during cell-assembly, there is certain deviation between the array substrate and the CF substrate. The deviation will result in the problems such as the reduced aperture opening ratio of the LCD and light leakage. Moreover, when the LCD has higher PPI, the aperture opening ratio is more seriously reduced. Meanwhile, the performances such as the brightness and the color gamut of products will also be reduced, but the energy consumption of the LCD will be increased.
In order to eliminate the deviation between the array substrate and the CF substrate, improve the aperture opening ratio, and reduce the cost, panel manufacturers have developed a technology for forming CFs and black matrixes (BMs) on an array substrate, namely color on array (COA) technology. The COA technology arranges the CFs and the BMs on the array substrate and hence can reduce the deviation between the array substrate and the CF substrate during cell-assembly, improve the aperture opening ratio, reduce the cost, and improve the display quality of products.